1. Field of the Invention
The present invention relates to a method for preparing a polyacrylamide aqueous gel plate for use in electrophoresis, and, more particularly, to a method for preparing a large quantity of polyacrylamide aqueous gel plates with homogeneous and high quality in a simple manufacturing procedure.
2. Description of the Background Art
Aqueous polyacrylamide gels have widely been used for electrophoresis analysis of in vivo components with a high molecular weight, e.g., protein, nucleic acid, and the like. Conventionally, polyacrylamide aqueous gels are used as electrophoresis media. They are prepared from a gel-forming solution charged into or coated onto a gel-supporter in the form of cylinder, plate, or film, or the like, on which the solution is polymerized by cross-linking to form an aqueous gel. Usually, plate-shaped gels (plate gels), which are relatively simple to prepare, easy to handle, and suitable for analyzing the plural of samples on the same conditions, are most widely used.
When preparing a gel plate, particularly in the case of a gel plate having a concentration gradient, the gel-forming solution is usually charged into each set of gel-supporter separately and individually, in most cases. According to this procedure, however, it is difficult to consistently produce a plurality of gel plates having a specified analytical performance because of the problem in the reproducibility in repeated charging. Moreover, it takes a long time and requires complicated steps to prepare a large quantity of such gel plates. In order to avoid these problems, it is necessary to introduce an expensive unit for charging of the solution and to employ a special mixing method for the preparation of gel-forming solutions. Thus, the method is not necessarily considered to be advantageous for industrial production.
On the other hand, the batch method, which utilizes a gel-forming container in which a plurality of gel-supporters are placed abreast and the gel-forming solution is charged into it to gelatinize, can afford a plurality of gel plates having the same quality by a simpler procedure as compared to the aforementioned individual, repeated charging method.
However, such batch method requires to stratify a water layer, an organic solvent layer, or the like on top of the gel-forming solution in order to prevent the gel-forming solution from contacting directly with air (oxygen) which prohibits the polymerization reaction to proceed. However, the stratified layer may mingle with the gel-forming solution producing unhomogeneous layers with different gel concentrations or a part of the layered organic solvent may remain in the gel plate. These can be the cause of deformation of electrophoresis images or deterioration of samples.
In addition, in a conventional batch method, since gel supporters are placed lengthwise in a container and the gel-forming solution is then charged full into the container, gelatinization takes place not only inside the gel supporters, but also along their peripheral portions. This often makes it difficult to take out the gel plates formed from the container or to peel off the gel plates each other. Because of this, the gel supporters may be broken or a gel supporter and the gel may be detached when they are taken out from the gel-forming container. Thus, such a conventional batch method often fails to produce an expected quantity of gel plates in a single operation. Furthermore, in the conventional batch method, the size of container or the number of supporters to be placed in a container is limited because of exothermic heat of polymerization and the like. This not only worsens the production yield and workability, but also imposes a limitation to the scale of the batch-size.
Accordingly, the present invention is to solve the above-mentioned problems in conventional batch processes and to provide a method for preparing polyacrylamide aqueous gels for electrophoresis having a high and uniform quality in a large quantity by a simple and easy procedure.
As a result of intensive studies, the present inventors found that a homogeneous gel can be obtained and deformation of electrophoresis images can be avoided by making the gel-forming container to an air-tight structure and eliminating the oxygen in the container or introducing oxygen-free gas into the container before charging the gel-forming solution. In addition, damages of gel supporters and detachment of gel and supporters at the time when they are taken out from the container can be prevented and exothermic heat of polymerization reaction can be suppressed by separating each gel supporter individually with partition members. These findings have led to the completion of the present invention.